Investigation of phycobilisome degradation using top down proteomics in Synechococcus elongatus UTEX 2973

Top down mass spectrometry analysis of Synechococcus elongatus UTEX2973 cyanobacteria under nitrogen starvation over time course of 4 hours. A number of phycobiliproteins covalently linked to phycocyanobilin pigments were detected as intact forms. Some of them showed partial degradation of the protein backbones or the pigment structures. NblA, a small protein that is believed to play a key role in phycobilisome degradation was shown to be highly correlated to nitrogen starvation based on its remarkable change of protein abundance.